1. Field of the Invention
This invention relates generally to printers. More specifically, the present invention relates to a thermal transfer printer which is suitably usable for printing, on an image print sheet, an image displayed on a color CRT.
2. Description of the Prior Art
Nowadays, video recorders and video players are wide-spread and used for preparing software images (moving images). Indeed, these devices are increasingly displacing cameras which are used for preparing hardware images (still images) on image print sheets.
However, it is often convenient or preferable to prepare both software and hardware images. For this purpose, it has been proposed to print out, on an image print sheet, an image displayed on a CRT connected to a video player. One typical method serving this purpose is to use a combination of a thermal head and an transfer ink ribbon, as disclosed for example in the Japanese journal entitled "Photo Industry (Imaging Part 2)" issued on Jul. 20, 1988.
For conveniently describing the prior art method disclosed in the Japanese journal, reference is now made to FIG. 16 of the accompanying drawings. As shown, the prior art method utilizes a rotary drum 1 for supporting an image print sheet A' against which a thermal head 4 presses a transfer ink ribbon B' fed from a supply reel 2 for winding up on a winding reel 3. The transfer ink ribbon typically carries a deposited layer of sublimation dye or colored meltable wax which is thermally transferred onto the sheet A' by the actuation of the thermal head, thereby printing an still image on the sheet.
The prior art shown in FIG. 16 is disadvantageous in the following points.
First, since the sheet A' is wound around the drum 1 and subjected to heat for printing, it will have a tendency to curl even after removal from the drum. Further, if the sheet A' comprises a relatively hard substrate made of resin for example, it cannot be wound on the drum. Moreover, if the sheet A' comprises a matrix of surface paper segments releasably attached to a substrate, the surface segments may be unexpectedly removed off the substrate at the time of winding the sheet around the drum or during the printing operation.
Secondly, since the sheet A' wound on the drum 1 provides an arcuate printing surface, it is difficult to insure uniform contact of the thermal head 4 with the sheet surface. If the thermal head is improperly arranged relative to the drum, uneven printing will result. On the other hand, it takes a lot of time and skill to properly arrange the thermal head relative to the drum.